Remove unused var (#1053)
Remove unused var (#1053)

Uglify caught this when I was testing to see what the updated min+gzip size was.
pygy/mithril.js,tivac/mithril.js,impinball/mithril.js,MithrilJS/mithril.js,barneycarroll/mithril.js,impinball/mithril.js,tivac/mithril.js,lhorie/mithril.js,MithrilJS/mithril.js,barneycarroll/mithril.js,lhorie/mithril.js,pygy/mithril.js